Human hair becomes soiled due to its contact with the surrounding environment and from the sebum secreted by the scalp. The soiling of hair causes it to have a dirty feel and an unattractive appearance. The soiling of the hair necessitates shampooing with frequent regularity.
Shampooing cleans the hair by removing excess soil and sebum. However, shampooing can leave the hair in a wet, tangled, and generally unmanageable state. Once the hair dries, it is often left in a dry, rough, lusterless, or frizzy condition due to removal of the hair's natural oils and other natural conditioning and moisturizing components. The hair can further be left with increased levels of static upon drying, which can interfere with combing and result in a condition commonly referred to as “fly-away hair.”
A variety of approaches have been developed to alleviate these after-shampoo problems. These approaches range from post-shampoo application of hair conditioners such as leave-on and rinse-off products, to hair conditioning shampoos which attempt to both cleanse and condition the hair from a single product.
Coacervate formation in a shampoo composition is known to be advantageous for providing conditioning benefits to the hair. The use of cationic polymers to form coacervate is known in the art, such as in PCT publications WO 93/08787 and WO 95/01152. Commonly used cationic deposition polymers include natural polymers, such as guar gum polymers that have been modified with cationic substituents. Guar gum polymers are galactomannans containing two mannose monomers with a glycoside linkage and one galactose monomer attached to a hydroxyl group of the mannose monomers (i.e., guar gum polymers have a mannose to galactose ratio of 2:1). The selection of a cationic guar deposition polymer with sufficient charge density and molecular weight results in sufficient deposition of conditioning agents.
However, to achieve this sufficient deposition of conditioning agents in shampoo or body wash compositions using a cationic guar polymer, a relatively high level of such cationic guar polymer generally must be deposited on the hair or skin. Moreover, the cost of such cationic guar polymer is relatively high. As a result, incorporation of cationic guar polymer can add to the manufacturing costs of such shampoo compositions. Additionally, these shampoo compositions typically are good for delivering wet hair conditioning, but are not capable of delivering satisfactory dry hair smooth feel.
Based on the foregoing, there is a need for a conditioning shampoo which can provide improved conditioning benefit for dry hair, while not interfering with the cleansing efficacy, nor providing negative feel to the hair when it is dried. Specifically, there is a need to provide long lasting moisturized feel, smooth feel, and manageability control to the hair when the hair is dried, yet not leave the hair feeling greasy, as well as to provide softness and ease of combing when the hair is wet.